Développer l'agroforesterie et les haies pour favoriser le stockage de carbone dans le sol et la biomasse végétale

Développer l'agroforesterie et les haies pour favoriser le stockage de carbone dans le sol et la biomasse végétal

Les engrais verts au service d’une fourniture d’azote et/ou du stockage de carbone?

Les engrais verts au service d’une fourniture d’azote et/ou du stockage de carbone? . Colloque chaire Agrosy

Train the youth! Effect of water stress and intercropping on peach tree growth after plantation

Train the youth! Effect of water stress and intercropping on peach tree growth after plantation. 3. European Agroforestry Conference (EURAF 2016

Gestion de l’entretien du sol et fonctionnement hydrique du vignoble

Ce numéro d'Innovations Agronomiques comprend les articles correspondant aux présentations du colloque « Viticulture et stress hydrique » qui s'est tenu à Montpellier le 17 juin 2014.National audienceIn Mediterranean regions, the strong inter-annual variability of rain regime makes difficult the achievement of stable agronomic and environmental performances in vineyards. It is due to both the conditions of winter soil water refilling and the water balance during grapevine vegetation cycle. Soil surface management offers technical control levers to manage water balance. Simulation-assisted design of strategies of soil surface management demonstrates that, on series of contrasted climatic years, adaptive strategies lead to changing nature, number and timing of technical operations, and to fairly stable resulting agronomic performances (yield, quality of products) and environmental impacts.En régions méditerranéennes, les fortes variations inter-annuelles de pluviométrie rendent difficile le maintien de performances agronomiques et environnementales stables dans les vignobles. Cela tient tout autant aux modalités de reconstitution des réserves hydriques en hiver qu’au bilan hydrique pendant le cycle de végétation de la vigne. L’entretien du sol offre des leviers techniques pour gérer ce fonctionnement hydrique. Une démarche de conception de stratégies d’entretien du sol par simulation permet de démontrer que, sur des séries d’années climatiques contrastées, des stratégies adaptatives permettent d’une part de faire varier la nature, le nombre et les dates des interventions techniques et d’autre part d’obtenir des résultats agronomiques (rendement, qualité des produits) et environnementaux (maîtrise du ruissellement) plus réguliers que des stratégies continues (sol nu permanent, enherbement permanent)

Gestion durable de la flore adventice en culture pérenne : enjeux et stratégies en viticulture

National audienc

“Cropping the roots” of agroforestry systems: applying moderate water stress and water competition at plantation to increase tree root biomass

“Cropping the roots” of agroforestry systems: applying moderate water stress and water competition at plantation to increase tree root biomass. 5. International Symposium for Farming Systems Design (AGRO2015

Differential effect of regulated deficit irrigation on growth and photosynthesis in young peach trees intercropped with grass

The effects of a moderate soil water deficit on several shoot growth variables (1st and 2nd order shoot growth and final leaves number, final height and final number of 2nd order shoots) and on net photo- synthesis were studied in young peach trees during the two years following plantation (January 2014). Trees were either fully irrigated (C), subjected to moderate water deficit (RDI) or subjected to moderate water deficit and associated with a grass-legume mixture on the entire orchard floor (RDI +G). Irrigationwas scheduled according to soil water potential target ranges in order to keep C trees above −0.02 MPa, i.e. at field capacity, and RDI and RDI + G trees between −0.04 MPa and −0.06 MPa. The level of water deficit obtained was moderate but yet significantly reduced by 50% overall tree growth in 2014 in RDI.This reduction was enhanced when water deficit lasted longer and when it was associated with grass in RDI + G. No reduction in growth variables occurred in RDI in 2015 due to the shorter duration of water deficit. Overall reduction was observed in 2015 in RDI + G mostly due to a carry-over effect of the pre- vious year. Net photosynthesis was reduced by the longer and more intense water deficit in 2014, but was not reduced during the soil water deficit in 2015. An indicator of plant process sensitivity to water deficit, taking into account the variable reduction with regards to the control, the water deficit intensity and its duration was used to classify shoot growth variables and net photosynthesis according to their sensitivity to water deficit. Variables could be classified according to the following order of ascending sensitivity: net photosynthesis <1st order final leaf number < final tree height <1st order final shoot length <2nd order final leaf number <2nd order final shoot number <2nd order final shoot length. Applying a moderate water deficit combined with full grass cover drastically reduces overall tree size due to grass competitio

Grapevine bud fertility and number of berries per bunch are determined by water and nitrogen stress around flowering in the previous year

Grapevine yield formation extends over two consecutive years (seasons 1 and 2). The inflorescence formation (around flowering in season 1) is crucial as it is involved in the formation of both the bunch number per vine and the berry number per bunch in season 2, that account for about 60% and 30% of year-to-year yield variation of grapevine, respectively. Light, temperature, water and nitrogen availability are known to affect this early stage. The aims of this work were to determine the critical periods during which inflorescence formation is sensitive to water and nitrogen stress and quantify their effects on it. To address these issues, we used a 3-year (2010-2012) field experiment (cv. Shiraz) in combination with a water balance simulation model (WaLIS) and a 6-year field experiment (cv. Aranel). In both experiments, different treatments were applied to create a gradient of water and nitrogen supply (treatments involved cover cropping, irrigation and fertilization). The grapevine yield and its components were recorded. Water and nitrogen status of grapevine were monitored throughout the season. Inflorescence formation was sensitive to water and nitrogen stress during a critical period that occurred between 400 and 700 degrees Cd after budburst in season 1. Bud fertility (number of bunches per shoot) and berry number per bunch in season 2 were significantly correlated with the fraction of transpirable soil water (FTSW), predawn leaf water potential and leaf nitrogen content at that time for both cultivars. Water and nitrogen stress during the critical period of season 1 determined 65-70% of grapevine yield in season 2. Our results show that the maximum yield that can be reached in season 2 is determined during the critical period of season 1 and they provide clues to estimate it. These results may help grape growers to adapt their practices (i) in season 1 to ensure a sufficient maximum yield for season 2 and (ii) to actually obtain the targeted yield in season 2 depending on the maximum yield determined in season 1

Indirect estimation of nitrogen reserves contribution to annual growth of grapevine

Contact: [email protected] crops such as grapevines are reliant on reserves – carbohydrates and nitrogen (N) – to support early seasonal growth stages, particularly during spring growth from bud break to bloom. Thus, reserves mobilization in perennial crops is considered to be a major determinant of vegetative growth and yield. Its estimation, particularly for N, is critical to adapt cover cropping strategy or fertilization management (Conradie, 2005). However, reserves measurements are very difficult to perform. Reserves are mainly stored in the roots (Bates et al., 2002; Zapata et al., 2004) and the practical problems associated with the excavation of whole grapevines make difficult to measure the whole roots biomass. We propose a two-step method to assess the N reserves contribution to annual growth of grapevine, calculating the N balance of a vineyard: (i) soil N balance over the 0-60 cm soil layer and (ii) grapevine N balance. For soil N balance, we take into account: soil N stock variation, net mineralization, denitrification, leaching, intercrop and grapevine N uptake from the 0-60 cm soil layer. Solving this balance leads us to estimate grapevine N uptake from the 0-60 cm soil layer used in the second step. For grapevine N balance, we consider N content of annual aerial parts (leaves, shoots, bunches), grapevine N uptake from the 0-60 cm soil layer, grapevine N uptake deeper than 60 cm, remobilization of reserves, losses through green harvest. Solving this balance leads us to estimate reserves remobilization and grapevine N uptake deeper than 60 cm. The estimation of N reserves contribution to annual growth was calculated over the bud break – bloom and the bud break – veraison periods. We used data from a Mediterrean vineyard (Celette et al., 2008, 2009 and 2010) involving two different types of soil cover management over two years (2005 and 2006): a bare soil obtained by chemical weed control (CWC) and a permanent intercrop (PI) composed of a mix of Festuca arundinacea L. and Lolium perenne. The contribution of N reserves and deeper grapevine N uptake to annual growth ranged from 30 % (CWC, 2005) to 100 % (PI, 2006) which represent respectively 8 kgN.ha-1 and 20 kgN.ha-1. This is consistent with other studies. For the intercropped treatment (PI) contribution of N reserves is always of 100 %. This can be due to the deeper grapevine root system due to the intercrop which allows grapevine N uptake deeper than 60 cm. This method is a simple way to estimate N reserves contribution to annual growth of grapevine without any root measurement, but the maximum depth for grapevine N uptake remains difficult to estimat